1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor substrate where a silicon thin film is formed on a substrate made of a low melting point material.
2. Description of the Related Art
A technique of forming (transferring) a silicon thin film, especially, a single crystal silicon thin film onto a substrate made of another material has been known as a so-called “bonding technique”. This technique has recently received attentions on account of being applicable to “flexible device” that can be applied even to a curved surface if a silicon thin film is formed on a low melting point organic thin film (film), for example. In addition, a technique of combining a single crystal silicon thin film onto a substrate made of a low melting point material (for example, low melting glass or the like) is one of the promising techniques because of a lower material cost than a cost for quartz glass or the like.
Hitherto, a SmartCut method (SOITEC method) has been known as a method for manufacturing a semiconductor substrate through a bonding process. In particular, the SmartCut method is a method for bonding a silicon substrate prepared by implanting hydrogen ions to a bonding surface side to generate “air bubbles” called “hydrogen blisters” at high density to a support substrate and then performing heat treatment at relatively high temperature, 500° C. or higher to cause “growth” of the “hydrogen blister” to thermally delaminate the silicon thin film based on the “bubble growth” to thereby manufacture a semiconductor substrate (for example, Japanese Patent No. 3048201 or A. J. Auberton-Herve et al., “SMART CUT TECHNOLOGY: INDUSTRIAL STATUS of SOI WAFER PRODUCTION and NEW MATERIAL DEVELOPMENTS” (Electrochemical Society Proceedings Volume 99-3 (1999) p. 93-106)).